Ditech Financial / Green Tree Servicing

During my time of being with this lovely group, I have never missed a payment and I can prove this. This organization sent me a 3 page letter telling me they were going to foreclose on me if I do not make my payments in a more timely manner. I am not alone here with this complaint, as I see others are having the same issue. What can I do? I have gathered all my bank statements and can send these as evidence. I tried to attach the years statements, but the file is too large.